Not sure why you lost AMC. I haven't heard anything about that channel.
There has been major changes involving Starz and Encore channels. There was a carriage disagreement (always about retrans $$$). The deal is that it will somewhat remain, but several dropped channels will remain dropped. For many users, Comcast has added several Screenpix (not to be confused with Streampix) and/or Epix channels.
Indieplex maybe? This area never had it to begin with but I know that's another channel that was lost. The only other one I can think of which was moved to the Sports Entertainment Package is TCM.